Fabrication and charactrization of large silicon micro-resistor array

Silicon Photo-Multiplier is a state of the art photo-detector, capable of detecting extremely low light flux with high gain (~10
⁵
) and high resolution. The SiPM consists of a large array of Avalanche Photo Diodes (APDs), connected to a common bias grid through individual series resistors and biased in `Geiger' mode. The series resistor acts as quenching mechanism, which stops the avalanche produced in an APD due to incidence of photon(s). Thus, the quenching resistor is an integral component to the device operation. We have fabricated a large array of silicon micro-resistors to be later integrated with SiPM. Amorphous silicon thin films were grown with Hot Wire CVD instrument at lower substrate temperatures of about 300 °C. In-situ boron doped films of thickness 100-200 nm were grown and patterned to create large array of micro-resistors. Statistical analysis of the resistance obtained from individual resistor testing was observed to be about 7% at 1-sigma level across the array of the resistors. Variation of the resistance across rows of the resistor array was comparatively lower to be ~5%. A systematic variation in the resistance was observed in particular direction of the array and thus could be attributed to the variation in the thickness of the deposited film. This article describes, characterization of in-situ doped silicon thin films obtained using HWCVD process as well as fabrication, characterization and analysis of the large silicon micro-resistor array.